BUILDING THE LAYOUT : PART 6

LAYING THE FOUNDATIONS

 

We have almost reached the stage where you can get on with laying the track but first you need to decide on the foundation or sub-structure for your permanent way. Of course you could just lay some pre-formed track sections on the ground, perhaps the patio or decked area, and off you go. That may be fine as a temporary arrangement but it is more a case of "playing trains" as opposed to building a semi-permanent representation of a railroad capable of prolonged operation in all weathers and you are unlikely to get the same sense of achievement or enjoyment.

For a more practical and lasting solution you will need to lay your track on a firm foundation. Well laid track will withstand the elements and ensure good running characteristics with the minimum of derailments.

The critical decision here is usually the height at which you wish to run and observe your railroad masterpiece. In some cases this may be largely pre-determined by the elevations of your chosen site. If the ground is undulating you will be wise to choose a level which involves the minimum amount of excavations and infilling as soil can prove amazingly heavy after the first few tons! You also need to take account of where you are likely to view the layout from. It is no good having a large part of it hidden from view if you like to see the trains running although conversely, some concealment is desirable as it can enhance the illusion that trains depart to a distant destination before re-appearing.

If you suffer from any kind of back problem you will prefer the layout to be at a convenient height that avoids stooping for any length of time. You might consider a raised layout either on a raised platform or bed.

Staying at ground level can sometimes seem the best option for the most part but even then it can be susceptible to earth movement, human or animal hazards (moles can be pest) or flooding.

Whatever you decide there are a wealth of published articles  (and website advice) on how to construct the roadbed and the best type of ballast to use (if any).  Every enthusiast will have their own preferences and these cover such a wide spectrum of opinion and solutions that I could not possibly hope to cover them all adequately here. The best I can do is provide a brief resumé of most of the popular methods and leave it to you to carry out further research. A selection of recommended website pages is to be found at the end of this article.

It seem to me that if you follow prototype practice you should not go far wrong as, by and large, rail travel has been proved to be the safest method of transport.

If you suffer from the dreaded mole or other burrowing pests ,like I do, you can always encase everything in concrete but you are not building a house so try not to go overboard if only for the fact that it can prove very difficult to modify your railroad at a later date and using a sledge-hammer can be hard work! Whilst we are the subject now is the time when you might give due consideration as to how you might wish to power the line and operate all the switches and lights, etc. It is much easier to incorporate channelling for wiring now rather than a later date.

The main reason for constructing a firm roadbed structure is to hold your track firm and secure in all weathers.

Let's examine the three main options. Low Level, Mid-Level and High Level.

LOW LEVEL

Establishing you line at ground level (or very close) can be the simplest and quickest solution to get things running in the shortest possible time. Having made the investment in good durable and weatherproof track you need to provide it with a solid foundation. Many modellers choose to imitate the real thing by laying the track in ballast where it is free to expand and contract according to the ambient weather conditions. This method can have also convey the most pleasing appearance. If you use flexible track or require more rigidity in the track you will need to employ some form of fixing at intervals. 

If you decide to build the railroad on the ground the earth will provide the necessary structure although it does tend to move and will never be as firm as a solid wall. However, if you do not want to be constantly battling with rampant grass and keep encroaching weeds at bay you will need to strengthen and help it along.

DIGGING AND LINING A TRENCH

This is usually done by excavating a shallow trench ( about 4" deep should normally suffice and about twice the width of the track) below ground datum level. Treat the channel with a proprietary weed-killer and then line with either a plastic or rubber membrane  with holes for drainage) or lengths of weed suppressant blanket designed for the purpose (with at least 5 years life) and readily available from garden and DIY centres. The life of these barriers can be extended by positioning lengths of newspaper (say 3/4 sheets) underneath.

EDGING 

I have found that a decorative terracotta tile edging strip (sometimes called "pavers") inset between the ballasted roadbed and any lawn makes it easier to mow and keeps the liner in place but again it's a matter personal preference. Alternatively you might favour a plastic or metal  lawn edging to create a barrier between grass and track or tannalised wood. This edging may have to last many years so go for the stronger, more rigid plastic, lawn edging if you can afford to do so. Some enthusiast recommend wood edging such as "rolled logs" for this purpose but I find straight laths somewhat inflexible and prone to rot even when treated.

SUB-ROADBED

Then fill the trench with about 3" of sharp ballast (shingle, crushed rock, chippings or anything you can lay your hands on) which will 'knit' together. Don't worry about finer particles or dust in the mix as this will actually help it to compact. Experts advise you to avoid pea gravel or indeed any material which has round as opposed to sharp edges as this type of stone will not lock into place and continuously shift. Make sure that the material is compacted and that there are no hollows or cavities which might lead to instability.

The following diagram conveys the basic principle:

 

TRACK BALLAST LAYER

Tamper the sub-roadbed course down and then lay a liberal covering of the final decorative / fixing ballast that you intend to use to actually hold the track in place and create the illusion of real ballast. Scale is not too important when selecting the type of finishing ballast to use as it is the final look that matters. Not too big but conversely not too small. Many outdoor railroad builders find 5mm granite chippings, crushed stone, decorative stone, or even cat litter are ideal. Many seem to have a convenient quarry source nearby who are happy to deliver "small" volumes but in my experience this is unlikely to be the case for most of us. 

THE RIGHT VISUAL IMPACT 

A note of warning. Don't underestimate the visual factor and use stone that is clearly the wrong colour and catches the eye for all the wrong reasons - garish ballast will always look out of place and distract from the aesthetic look of your line. Go for something that will blend in with its surroundings and almost disappears. Remember also that, like everything else, ballast can change its appearance over time as the elements get to work and the material ages naturally. Just go with something that you feel comfortable with and will hold the track in place.

LAYING THE TRACK

Next lay the track sections in position infilling any shallow areas and conversely reducing parts of the roadbed where there are bumps.  Sometimes you can agitate the track slightly to ensure a firm connection with the substrate. When you are satisfied with the result and have checked grades or inclines with a spirit level finish off by applying a further light covering of decorative ballast ensuring that any gaps between the sleepers (ties) and at the sides are filled to bed in the track. It sometimes helps to use a small brush to achieve the desired "worked in" effect and remove any excess ballast.

CHECKING TRACK CLEARANCES

Make sure that no ballast is high enough to foul the passage of any locomotive or rolling stock paying particular attention to any point blades. In areas where there is a possibility of disturbance, say from animals, garden leaf vacuuming or strimming it is often worth spraying the ballast with a diluted PVA glue solution (adding a few drops of your favourite washing-up liquid) to stabilise the ballast as much as possible. It is generally advisable to use a small spirit level to make sure the track is just that. Nothing should be higher than the top of the rail.


MID-LEVEL ROADBEDS

I have used this term to mean anything between ground and track that is elevated just off the ground as opposed to knee to waist high (or possibly even higher). 

Why should you opt to build a raised railroad when a ground level one would seem to offer the simplest solution?

Firstly raised roadbeds are considered to be easier to maintain and involve much less bending down which can be an important consideration for those who are not in peak physical condition. 

Secondly, the higher the railroad the closer it is to eye-level and the better the vantage point for observing railroad operations.  It is also easier to see and appreciate the model detailing which can sometimes be missed if viewing directly from above.

The third reason advanced is that it this method makes it easier to compensate for difficult and varying terrain. If your line traverses several different elevations on its journey round your garden this may be the optimum solution. 

A raised roadbed is much less susceptible to ground shift, erosion, flooding, frost damage, landslips, and burrowing animals (remember the dreaded moles) thus ensuring optimum reliability.

A lastly there is less opportunity for weeds and such-like to encroach on your line causing derailments making maintenance a lot less onerous. 

Thus it is often more practical to install the roadbed slightly off the ground and this can be achieved with all manner of materials. Some enthusiasts always use tannalised wood (not creosote which whilst cheap is no longer politically correct and can sometimes react with the plastic sleepers) whilst others favour brick, stone or concrete blocks (heavy or light thermalite) to achieve the right working height. Some are easier to work with than others and you may need to experiment to find the best solution compatible with your building skills.

Embankments can be "earthed up" and planted with suitable ground cover plants to conceal any bricks or concrete and help stabilise the whole edifice.

 

 

 

HIGH LEVEL

In this section we are dealing with railroads that are positioned at least 18" (450mm) off  the ground to achieve maximum visual impact. This can involve quite a bit of work but you don't have to tackle it all in a day. Take your time and make full use of any "free" building materials that neighbours may be only too grateful to dispose of.  

If there is a downside to high level railroads it is probably that they are more expensive (both in time and materials) and more difficult to landscape.

Some modellers spend a lot of time and inordinate effort recreating the physical landscape with tons of real rock, shingle, and earth whilst others make maximum use of existing wall and fences to attach a roadbed. I have already mentioned the importance of having a proper viewpoint for maximum realism and this can sometimes involve building large physical structures such as retaining walls with wooden sleepers, stone or concrete. An existing wall or fence can also provide a useful means of gaining height. There really is no limit to what you can do to achieve realism or your imaginary railroad empire. 

TRADITIONAL METHODS

The most common method is to build on a raised base of 5" (130 mm) wide flat timber planks (or decking board, gravel board, etc) fixed to 75mm square tannalised (pressure treated) wooden posts sunk into the ground or into proprietary heavy gauge metal spiked supports such a Metpost (other makes are available). Both techniques can be reinforced with concrete for extra strength. Posts need to be installed about every 24" - 36" (as close as 18" on curves).  

For maximum rigidity you can also attach longitudinal supports ("stringers") to each side of the uprights before fixing the top planks in place.

The boards will be exposed to the elements so a secondary coating of wood preservative or even mastic is always a good idea. You can also fix some strips of roofing felt to the top and sides for added protection and to create a rough surface for affixing the ballast. A strip of metal or wood strip screwed or nailed into the sides of the plank will help to keep the ballast in place.  

NOVEL SOLUTIONS

Some modellers have experimented with other more novel approaches to off-ground elevated tracks including zinc trays and even "U" or square profile PVC guttering (which has the added benefit of being waterproof). While these materials may be more durable they tend to be more expensive and certainly more difficult to bend round curved sections. If you are interested in the potential for these solutions (especially the flexible HDPE Roadbed technique which does go round corners) you may find the following references of particular interest (click for hyperlink) and whilst the articles describe an O Gauge layout the principles are capable of being applied to any scale or gauge:

 

HDPE Flexible Railroad Primer

The B&P Garden Railroad (Part 1)

The B&P Garden Railroad (Part 2)

The B&P Garden Railroad (Part 3)